And in contrast to them stand: الَّذِينَ سَعَوْا فِي آيَاتِنَا (5) i.e. those who made efforts to find faults with Our verses and tried to stop people from believing in them.
The word: مُعَاجِزِينَ which appears immediately after the verse cited above means that this effort by them was as if they would render Us helpless in seizing them and would thus go scot-free from having to be present on the last day of Qiyamah.
The sentence that follows immediately after: أُولَـٰئِكَ لَهُمْ عَذَابٌ مِّن رِّجْزٍ أَلِيم ; means that these people shall receive punishment, a severe punishment that will be painful.